Finally, a rule of thumb for rounding off numbers in which the digit to be dropped is a 5 is always to make the last digit of the rounded-off number even:
1.35 = 1.4
1.25 1.2
1. Express the following quantities in scientific notation and indicate how many significant
figures each has
(a) 12,200 (b) 12.200.0 (c) 0.003040
2. Express the following quantities in standard decimal form and indicate how many signif-
icant figures cach has.
(a) 1 34 x 10$
(b) 1.340 X 10-2
(c) 0.00420 X 106
3. How many significant figures would the solution of each of the following problems have?
What are the solutions of (c) and (d)?
(a) (5.74)(38.27) (0.001250) (c) 1.000 + 10.2
(b) (1.76 X 100.12 x 10-6) (d) 18.76 – 7
4. Round off each of the following numbers to three significant figures.
(a) 1465 (b) 13.35 (c) 1.765 X 10-1
5. When the value of a number is given, the significant figures provide an indication of the
unccrtainty in the value for example, a value of 2.7 indicates that the number lies between
2.65 and 2.75. Give ranges within which each of the following values lie.
(d) 2500
(b) 4.30
(e) 2.500 X 103
(1.778 x 10-
Results